Bulked,balanced yarn and method for manufacture thereof



United States Patent 3,485,030 BULKED, BALANCED YARN AND METHOD FOR MANUFACTURE THEREOF Hendrikus Jan Smit and Antonius J. F. Hollweg, Emmen, Netherlands, and Jacobus Johannes Jonker, Mexico City, Mexico, assignors to American Enka Corporation, Enka, N.C., a corporation of Delaware No Drawing. Filed Oct. 2. 1967, Ser. No. 671,945 Int. Cl. D02g 3/02 U.S. Cl. 57140 ABSTRACT OF THE DISCLOSURE A bulked, balanced yarn made up of multi-filament components, each of which has substantially no twist and has a high twist-liveliness, said yarn further being characterized by the following combination of properties:

(a) a tenacity of at least 450 grams per 100 denier;

(b) an elongation at break, measured from the straightened condition, of less than 25%, and preferably of from 18 to 20%; and

(c) a crimp rigidity of less than 40% and preferably of from 30' to 35%.

An improved method for the manufacture of the bulked, balanced yarn is also disclosed. This method comprises subjecting a plurality of yarn components, preferably two multi-filaments components consisting of a thermoplastic material, while temporarily in a state of high twist, to a heat-setting treatment, and subsequently so plying the components together to form a yarn that the twist liveliness of each component is balanced by that of the other components, the components that are set while temporarily in a state of high twist having an elongation at break of less than 25 a tenacity of at least 700 grams per 100 denier and said high twist being at a level at which the expression nT is between the values 2.4)( and 3 X 10 wherein n is the number of turns per meter and T is the linear density in denier of each component.

The invention relates to a bulked, balanced yarn made up of one or more multi-filament components, each of which has hardly any or substantially no twist and has a high twist-liveliness. In addition, this invention relates to the method for the manufacture of such yarn.

It is known to produce bulked, balanced yarns by plying together, for instance, by twisting together, a plurality of filamentary components each of which has been subjected to a setting treatment While temporarily in a state of high twist. On account of the components having been set, while in a state of high twist, they are very twist-lively. This liveliness manifests itself in the yarn being elastic and, when allowed to go slack, in the yarn having increased bulk. Although the bulk and elasticity of these components are often desirable properties, their twist-liveliness presents great difficulties when they are to be processed. This disadvantage is obvitated by so plying together a plurality of filamentary components, each of which has been subjected to the above-mentioned treatment, so that the twist-liveliness of each of the components is balanced by that of the other components.

It will be understood that these treatments can very suitably be applied to thermoplastic synthetic yarns, In this regard, it is also known to apply setting treatments to yarns that are temporarily in a state of high twist and that are made of materials other than these synthetic materials; this may be effected for instance, with the aid of swelling agents or synthetic resins. It should also be recognized that instead of plying the components by twisting them together, a method is known in which plying is 6 Claims 3,485,030 Patented Dec. 23, 1969 ice effected by interlacing the components with their filaments with the aid of a turbulent air jet.

The first application of the yarns indicated as known Was as elastic yarns. Later, it was found that it is also possible to reduce the high elasticity of these yarns, after which highly bulked, but less highly elastic yarns were obtained. To this end, the components, after they have been subjected to a setting treatment while in a state of high twist, must be allowed to relax and subsequently be subjected to a second heat-setting treatment.

This last-mentioned method has considerable disadvantages. First, the method requires two setting treatments, which adversely influences the strength of the yarn, and also involves the use of additional power. Also this method of treating further requires extra provisions on existing machines, which makes them difficult to operate and very-costly.

The present invention, advantageously, provides a bulked, balanced yarn of a type similar to that indicated as known, which can be manufactured by a method similar to the known method for the manufacture of highly elastic yarn, without these disadvantages.

The present invention thus contemplates a yarn that shows the following combination of properties;

(a) A tenacity of at least 450 grams per denier;

(b) An elongation at break, measured from the straightened condition, of less than 25% and preferably of from 18 to 20%; and

(c) A crimp rigidity of less than 40% and preferably of from 30 to 35%.

More particularly, in accordance with this invention, preference is given to a yarn that is made up of only two components, each of which has a denier of from to 300 and is composed of filaments having a denier of from 4 to 8, and preferably of about 6. By choosing the appropriate starting material, a yarn may be obtained which, if treated by a method similar to that hitherto known for the manufacture of highly elastic yarns, is given the above-mentioned properties.

In this connection it should be noted that by crimp rigidity is to be understood the quotient of the length by which a crimped yarn can contract and the straightened length of this crimped yarn.

The yarns of this invention are manufactured by a method in which one or more yarn components consisting of a thermoplastic material are, while temporarily in a state of high twist, each subjected to a heat-setting treatment, and subsequently plied together to form one yarn, and in which the yarn components that are set While temporarily in a state of high twist have an elongation at break of less than 25% and preferably of about 20% and a tenacity of at least 700 grams per 100 denier.

In accordance with this invention it has been found that the crimp and the elasticity of the yarn obtained may be influenced by the twist level and the choice of the yarn denier. Moreover, the yarns obtained show the most attractive crimp if, according to the invention, two components are temporarily twisted to high twist levels at which the expression n /T is between the values 2.4 10 and 3x10 wherein n is the number of turns per meter and T is the linear density in denier of each component. It is also to be preferred, during the time the components are kept at the high twist levels, to stretch them by about 1%, and then to separately wind them while allowing them to contract by about 5%, and then to assemble the various, preferably two, components and to twist them together to about 100 turns per meter.

The yarn thus obtained has a high bulk, and shows, when made into knitted fabrics to be used, for instance, for sweaters, an original, moss-like appearance. Naturally,

this yarn is not very suitable to be used in elastic socks. Yet it has still been found possible to make this yarn, according to the invention, suitable also for use in elastic socks, the higher bulk then being an additional advantage. According to the invention the components of this yarn should be twisted together with a tensioned elastomeric thread which need only constitute 3 of the yarn weight. This elastomeric thread may be made of any suitable elastomer such as rubber or a segmented elastomer having an elastic character.

The invention will be further understood by reference to the following examples:

Example I A yarn having a final denier of 210 and composed of 35 filaments was manufactured from poly-e-caprolactam (nylon-6) by the melt spinning process. The yarn was spun at a speed of 400 meters/minute. Subsequently, the yarn was drawn on a ceramic pin at a draw ratio of 5.25, and immediately thereafter stabilized by passing it over a plate heated to 180 C. The yarn obtained has a tenacity of 770 grams per 100 denier and an elongation at break of about 20%.

Two yarns of this type are each subjected to a falsetwisting treatment, one yarn being given a false-twist in S-direction, and the other in Z-direction. The false-twisting spindles are driven at a speed of 120.000 r.p.m., as a result of which a false-twist of 1929 turns per meter is inserted into the yarns. In the false-twistin-g zone the yarns are stretched by 1%. The false-twist is set by passing the yarns through an oven heated to 200 C. The yarns withdrawn from the false-twisting spindles are, without inserting any twist into them, separately wound, the yarns being allowed to contract by Finally, an S-false-twisted yarn and a Z-false-twisted yarn are twisted together to 95 turns per meter on a doubler twister.

The yarn obtained has a tenacity of 500 grams per 100 denier, and an elongation at break of 18%. The crimp rigidity was measured to be 30%. The yarn has a high bulk and can be knitted very satisfactorily to garments, such as sweaters and jerseys. This yarn is particularly suitable to be knitted into coarse fabrics.

Example II An S-false-twisted yarn and a Z-false-twisted one were manufactured in the manner described in Example I. However, in this case, while twisting these two yarns together at 95 turns per meter an elastomeric monofilament having a denier of 40 was incorporated. The elastomeric thread was first stretched by 220%; as a result of which the elastomeric thread was under tension when it was incorporated in the plied yarn. Consequently, the final yarn has a more elastic character, so that it is very suitable to be used for the manufacture of socks.

Example III In a control experiment a yarn was manufactured by the hitherto known method for the manufacture of elastic yarns. Two yarns which, after having been drawn, had a denier of 210, and which were composed of 35 filaments, were manufactured from poly-e-caprolactam by melt spinning at a speed of 1100 meters/ minute. These yarns were drawn at a draw ratio of 3 on a porcelain pin, without any additional stabilization treatment being carried out at an elevated temperature. The yarns thus obtained have a tenacity of 500 grams per 100 denier and an elongation at break of 35%, and are thus of the type of polyamide yarns that is usually employed for textile purposes. Such yarns are therefore usually employed as starting material for a texturing treatment on false-twisting machines.

In a manner corresponding to that described in Example I, two of these yarns were set while temporarily being in a state of high twist, wound and subsequently assembled and twisted together. The yarn thus obtained has a crimp rigidity of 60%, so that it clearly falls in the category of elastic yarns. This yarn is unsuitable to be knitted into garments such as sweaters and jerseys.

The results of this example, when compared with those of Example I thus show that the tenacity and elongation at break of the yarn components used are important parameters and that failure to use the correct yarn components results in formation of elastic-type yarns unsuitable for the applications for which the yarns of this invention are particularly effective.

What is claimed is:

1. A bulked, balanced yarn made up of multi-filament components, each of which has substantially no twist and a high twist-liveliness, said yarn further being characterized by the following combination of properties:

(a) a tenacity of at least 450 grams per denier;

(b) an elongation at break, measured from the straightened condition, of less than 25%; and

(c) a crimp rigidity of less than 40% 2. The yarn of claim 1 in which the elongation at break is from 18 to 20% and the crimp rigidity is from 30 to 35% 3. The yarn of claim 1, comprising two components, each of which has a denier of from to 300 and is composed of filaments having a denier of from 4 to 8.

4. The yarn of claim 1 in which the components are twisted together with an elastomeric thread which constitutes about 3 of the yarn weight.

5. In a method for the manufacture of a bulked balanced yarn wherein yarn components consisting of a thermoplastic material are, while temporarily in a state of high twist, each subjected to a heat-setting treatment, and subsequently so plied together to form a yarn that the twist-liveliness of each component is balanced by that of the other components, the improvement which comprises using, as the yarn components, two multifilament components, each (1) being temporarily twisted to a high twist level at which the expression m/T is between the values 2.4)(10 and 3 X10 wherein n is the number of turns per meter and T is the linear density in denier of each component, each (2) having an elongation at break of less than 25% and (3) each having a tenacity of at least 700 grams per 100 denier.

6. The method of claim 5 which is further improved by stretching said components by about 1% during the time they are kept at the high twist levels, subsequently separately winding said components While allowing them to contract by about 5%, and then assembling and twisting the two components together to about 100 t-urns per meter.

References Cited UNITED STATES PATENTS 2,197,896 4/1940 Miles 57-140 2,846,840 8/1958 Billion 57-157 3,117,410 1/ 1964 Crouzet 28-72 3,125,848 3/1964 Baebler 57-140 3,343,363 9/1967 Stow 57-140 3,365,768 1/1968 Brown et a]. 57-140 XR FOREIGN PATENTS 499,894 2/1954 Canada.

DONALD E. WATKINS, Primary Examiner US. Cl. X.R. 57-157 

